1. Field of the Invention
This invention relates to papers made with fibrids containing a polymer or copolymer derived from a monomer selected from the group consisting of 4,4′diaminodiphenyl sulfone, 3,3′diaminodiphenyl sulfone, and mixtures thereof. Such papers have high thermal stability and accept ink more readily than papers made solely with aramid fibrids.
2. Description of Related Art
Papers made from high performance materials have been developed to provide papers with improved strength and/or thermal stability. Aramid paper, for example, is synthetic paper composed of aromatic polyamides. Because of its heat and flame resistance, electrical insulating properties, toughness and flexibility, the paper has been used as electrical insulation material and a base for aircraft honeycombs. Of these materials, Nomex® of DuPont (U.S.A.) is manufactured by mixing poly(metaphenylene isophthalamide) floc and fibrids in water and then subjecting the mixed slurry to papermaking process to make formed paper followed by hot calendering of the formed paper. This paper is known to have excellent electrical insulation properties and with strength and toughness, which remains high even at high temperatures.
Generally such aramid papers are difficult to color and print; for some applications aramid papers are coated to provide a better surface for printing of bar codes and other indicia. This requires an additional step after paper manufacture and the resulting waste that is generated by an additional manufacturing step. Therefore, there is an ongoing need for high performance papers with improved properties, particularly papers that will accept ink or color more readily than high performance papers such as known aramid papers.